The present invention relates to the field of machines for cutting and rewinding adhesive and non-adhesive tapes of different sizes.
The present invention provides, in particular, a fully automatic machine, that longitudinally cuts tapes to desired widths and rewinds the longitudinally cut strips around cores having different external nominal diameters. The art includes a machine which includes a jumbo roll and an unwinding stand, separated from the machine itself. Using rollers of different diameters, the machine unwinds tape from the jumbo roll. The prior art machine automatically supplies the tape with one or more cross tabs made of paper or plastic film. The prior art machine then cuts the tape longitudinally in strips of predetermined widths by one of the three following cutting systems: a razor blade cutting device, a system for score cutting by means of a hardened cylinder and circular dinking dies, or circular blades and counterblades. These cutting systems are well known.
According to the present invention, the tape strips are rewound around cores of desired external diameters. The tapes are cut when the rolls of rewound strips reach the desired length. Then the rolls are discharged into a basin.
Subsequently, rolls are discharged onto a suitable conveyor belt. The same station that discharges the rolls also carries out the loading of new cores.
An aim of the present invention is a machine of the above mentioned type, which is provided with one or more rewinding turrets. Each of these turrets is supplied with three stations as follows: a first station for rewinding previously cut tape strips, a second station for automatically cutting and fastening the cut end of the tape, and a third station for unloading rewound rolls and loading new cores. The three stations are angularly arranged 120 from each other.
The machine is operated by rotating one of the turrets. This turret is called the drive turret and is connected to a hydraulic cylinder/free wheel system. The hydraulic cylinder/free wheel system moves the drive turret. Through a group of gears joined in series, the other turrets are also driven with the drive turret so that all of the turrets are cylindrically operated through the three 120.degree.-spaced positions.
In addition to the sequential movement through three 120.degree.-steps, the rewinding station must be driven when it is in the rewinding position. This further driving of the rewinding station is performed by means of a further rewinding motor. The rotation speed of the rewinding motor is adjustable to accommodate the type of tape being rewound. Thus, each rewinding turret includes three shafts corresponding to the three stations. The shafts are rotatably driven by means of the rewinding motor and a toothed or belt (or gear) transmission. Using friction means, the rotation is transmitted to the core-holders. The rotation of the shafts is carried out by disengaging a clutch connected to the rewinding motor and the roll rotation drive shaft and operating an external belt (or spur gear) transmission driven by a second rewinding motor. This causes the rewinding shaft to rotate.
When the rewinding shaft is joined to the belt transmission (or gear series) through a pair of gears external to the turret, it transmits movement to a series of rewinding shafts. Expanding plastic material core-holders for supporting the cores are located on the shafts.
Each core-holder is driven, during the rewinding phase, by a tooth belt and pulley (or a series of gears). One of them is assembled as an idle element on the shaft and locked between a series of spacers introduced on the shaft and driven by the rewinding motor.
When these spacers are joined by friction with the pulley (or gear) they then rotate together with the pulley (or gear) and the rewinding shaft. The torque transmitted by the drive pulley (or gear) is a consequence of the friction produced between the pulley (or gear) and the spacers that lock the same. The spacers are pressed by two springs which are pressed by two corresponding opposite adjusting ring nuts at the two ends of the shaft. When the desired rewinding length is achieved, the turret rotates through 120.degree. under the action of the hydraulic cylinder. Thus, rewound rolls are brought from the rewinding station to the cutting and automatic cut end fastening station.
According to another feature of the invention, each turret is provided with a cutting unit between the first rewinding station and the second cutting and automatic cut end fastening station. The cutting unit includes a blade assembled on a trolley or the like. Each turret is provided with an idle roller, this roller automatically sticks adhesive tape onto its own external surface thereby ensuring that the just cut tape end is retained. The idle roller also stretches the tape so that the adhesive tape can then be wound on a new core. Each rewinding turret includes three idle rollers. The rollers are assembled between the three stations. The rollers are equally spaced among the stations.
According to another feature, each rewinding turret includes a loading and unloading unit. This unit includes a puller. After a 120.degree. rotation, the puller pulls a rewound roll and makes the roll fall into an underlying basin and introduces a new core onto the free core-holder.
The whole core loading/unloading unit is assembled on a mobile frame. The frame slides along fixed guides by means of sliding rollers. The sliding motion is driven by a hydraulic or pneumatic cylinder. The machine includes internal parts for holding conveyor belts for the ejection of finished rewound rolls. The mobile unit allows for easy inspection of these internal parts. That is, the mobile unit can be extracted away from the machine to facilitate inspection.
Further, the loading/unloading unit, during its return movement and after having introduced a new core onto a coreholder, causes trap doors of the basins to open. Thus, rewound rolls within the basin fall in tidy sequence into underlying conveyor belts. This movement is performed by hydraulic, pneumatic or electronic means.
Subsequently, after the return movement, the loading/unloading unit is fed through a series of channels that convey spaced cores. The cores were previously introduced into the channels by a feeder from a hopper.
The channels are sloped. Thus, when a core stop device is opened, a plurality of new cores will be drawn from the loading/unloading unit to be charged into the loading and unloading station of each of the various rewinding turrets.
Further, when the loading/unloading unit draws the cores, the presence of core-holders is sensed by means of an electric sensor. The sensor includes a metallic blade which is fixed to the loading/unloading unit and joined to an electric system. If a core is not present, the blade contacts the metallic core stop device and trips a switch to lock the loading and unloading unit.
The above mentioned features and objects of the invention will be understood more clearly after considering the following description of a preferred embodiment, as shown in the annexed drawings, in which: